Food products that are substantially flowable, such as margarine, butter, sour cream, ice cream, yogurt or the like, typically are packaged in individual containers for retail sale and consumer use. Packaging of these types of food products is ordinarily effected with the use of fill pump devices and associated container conveyors that present containers in a continuous, sequential manner to the filling device which is operated to dispense food product to each of the containers.
In such systems, precise control of the filling device is necessary in order to assure that each container receives the desired quantity of product. In practice, such precision can be difficult to achieve due to inherent fluctuations in product consistency and temperature as well as the periodic start-up and shut-down of a filling line which typically complicates accurate filling of the containers.
Existing systems typically are either pneumatically controlled or cam-operated. Pneumatically controlled systems typically include pneumatically actuated pumping devices including a piston for dispensing the food product into the associated containers when the piston is advanced during a container-filling stroke. Pneumatic systems, however, are affected by inevitable fluctuations in air supply pressure, the limited service life of the pneumatic cylinders and the attendant problems of maintaining the various seals and like components of the system.
Cam-operated filling systems can provide enhanced product weight control as well as consistent, dependable operation of the pump device, which can be operated independently of or mechanically linked to the container conveyor. However, cam-operated systems cannot always deliver the desired pump piston velocity during initial start-up of the filling line, which can sometimes affect the appearance of the food product with which the containers are being filled. Additionally, such systems require the provision of cams, linkages, etc. necessary to effect pump operation.
It therefore would be desirable to provide a product filling method and apparatus which operates independently of the container conveyor and permits versatile, dependable operation of a filling system while maintaining the appropriate product weight and appearance under a wide variety of operating conditions. It would also be desirable to provide a system which minimizes product seals, operating linkages, and like components for reduced cost and enhanced reliability.